# Situation: After a typhoon flooded a low-lying barangay, the nurse at the Rural Health Unit (RHU), which also serves as an animal bite treatment center (ABTC), sees clients with animal bites and flood-related illness. A 42-year-old rice farmer who waded in floodwater 10 days ago has had fever, headache, and calf pain for 4 days. Which finding MOST indicates that he needs urgent hospital referral?

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> subject: Nursing Practice I — Community Health Nursing

## 문제

Situation: After a typhoon flooded a low-lying barangay, the nurse at the Rural Health Unit (RHU), which also serves as an animal bite treatment center (ABTC), sees clients with animal bites and flood-related illness.

A 42-year-old rice farmer who waded in floodwater 10 days ago has had fever, headache, and calf pain for 4 days. Which finding MOST indicates that he needs urgent hospital referral?

## 보기

1. A temperature of 39 °C with a severe headache
2. Scant, dark urine that began yesterday **✔ 정답**
3. Tenderness of both calves when they are squeezed
4. Redness of both eyes without any discharge

**정답: 2**

## 해설

Fever, calf pain, and conjunctival suffusion after floodwater exposure point to leptospirosis. Reduced, dark urine suggests acute kidney injury, a sign of severe leptospirosis (Weil disease) that needs hospital care such as IV antibiotics and possible dialysis. The other findings are typical of the mild form.

## 심화 해설

Clinical context A 42-year-old farmer presents with fever, headache, and calf pain 10 days after wading through floodwater. This triad strongly suggests leptospirosis, a spirochetal infection transmitted through contact with water contaminated by rodent urine. The organism enters through broken skin or mucous membranes, and after an incubation period of roughly 7–14 days, it disseminates hematogenously and invades the liver, kidneys, lungs, and vascular endothelium.

Why option 2 is the priority Scant, dark urine that began yesterday signals oliguria and acute kidney injury (AKI), which marks progression from mild leptospirosis to the severe icteric form known as Weil disease. In leptospirosis, the spirochetes migrate into the renal interstitium and tubules, triggering tubulointerstitial nephritis and impaired tubular reabsorption. The resulting decline in urine output reflects a falling glomerular filtration rate, and the dark color suggests concentrated urine or myoglobinuria from concurrent muscle injury. Key point! Oliguria is a clinical red flag for impending renal failure and requires inpatient management with intravenous antibiotics and, in some cases, dialysis.

The scoping review by Rosengren et al. identified oliguria as one of the simple clinical findings repeatedly associated with severe leptospirosis, alongside abnormal respiratory findings and hypotension [1]. This supports the idea that reduced urine output is not merely a symptom but a marker of organ dysfunction that predicts a complicated course. In a prospective study of hospitalized febrile adults in India, leptospirosis was associated with greater severity, higher resource utilization, and increased mortality compared with other acute febrile illnesses, underscoring the need to recognize early signs of organ involvement [2].

Why the other options are less urgent Watch out! Fever of 39 °C with severe headache, bilateral calf tenderness, and conjunctival suffusion are all classic features of the anicteric, or mild, form of leptospirosis. They reflect the early immune phase of the illness, when the organism circulates in the blood and triggers a systemic inflammatory response. These findings warrant antibiotic therapy and close monitoring, but they do not by themselves indicate that organ failure has already begun.

| Finding | Clinical meaning | Level of urgency |
| --- | --- | --- |
| 39 °C fever with severe headache | Systemic inflammatory response during leptospiremic phase | Moderate; requires treatment but not immediate referral |
| Scant, dark urine | Oliguria indicating acute kidney injury and possible Weil disease | High; urgent hospital referral for IV antibiotics and dialysis evaluation |
| Bilateral calf tenderness | Myositis from spirochetal invasion of skeletal muscle | Moderate; supportive finding in early leptospirosis |
| Conjunctival suffusion without discharge | Vasculitic dilation of conjunctival vessels; characteristic but not organ-threatening | Moderate; helps confirm diagnosis but does not indicate severity |

Diagnostic and management implications In the Philippines, where leptospirosis is endemic, clinicians often rely on clinical judgment because rapid diagnostic tests have variable accuracy . The presence of oliguria should therefore lower the threshold for referral even before serologic confirmation is available. The overlap of leptospirosis with other tropical febrile illnesses such as Q fever and rickettsial diseases can delay diagnosis, but the development of renal impairment narrows the differential and signals a need for aggressive supportive care .

The transition from the anicteric to the icteric phase is marked by the appearance of jaundice, renal failure, hemorrhage, or pulmonary involvement, and any one of these is sufficient to classify the illness as severe. Among the options, only scant dark urine represents an established organ complication, making it the finding that most strongly indicates urgent hospital referral.References (research sources)

- [1]The Characteristics of Patients That Develop Severe Leptospirosis: A Scoping Review.Research articleRosengren P, Johnston L, Ismail I, Smith S, Hanson J. (2025) · DOI: 10.3390/pathogens14121268

- [2]Leptospirosis is associated with severity, increased resource utilization, and mortality among acute febrile illnesses from Karnataka, Southwestern India.Research articlePanjabi GR, Joseph G, Saravu K. (2026) · DOI: 10.1080/07853890.2026.2687164

## 임상 시나리오

Leptospirosis Triage: Recognizing Severe DiseaseWhen floodwater exposure turns dangerous
After floodwater exposure, the triad of fever, calf pain, and conjunctival suffusion suggests leptospirosis. Most cases are mild, but progression to Weil disease requires urgent referral.

The single most important warning sign is oliguria — scant, dark urine. This indicates acute kidney injury from tubulointerstitial nephritis and marks a shift from mild to severe disease.

CautionDo not wait for jaundice or hypotension. New-onset reduced urine output in suspected leptospirosis is a red flag for renal failure and warrants immediate hospital care with IV antibiotics and possible dialysis.

## 핵심 개념

- **leptospirosis** — A spirochetal infection transmitted through water contaminated by rodent urine, entering via broken skin or mucous membranes.
- **Weil disease** — Severe icteric form of leptospirosis with jaundice, renal failure, and hemorrhage.
- **oliguria** — Abnormally low urine output, a red flag for acute kidney injury in leptospirosis.
- **conjunctival suffusion** — Redness of the conjunctiva without purulent discharge, characteristic of leptospirosis.
- **acute kidney injury** — Rapid decline in kidney function, often signaled by reduced, dark urine in severe leptospirosis.

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